(a) Field of the Invention
The present invention relates to a charging device, and more particularly to one having its shunt and voltage division controlled by voltage detection at lower production cost to provide the same function when compared to conventional charging circuit with complicate wiring design.
(b) Description of the Prior Art
The prior art of voltage detection usually requires a comparative circuit and an expensive main switch with larger power capacity and a larger current to fully cut off the charging current.
The primary purpose of the present invention is to provide a circuit to control cut-off charging after saturation with shunt and voltage division by a switching device of smaller power capacity. To achieve the purpose, voltage detection is used So execute shunt and voltage division. Within, in the course of detecting a charging voltage rise in a (dis)chargeable secondary battery, shunt is applied to actively decrease the charging current for controlling a main switch connected in series with the charging circuit and to provide, when the charging is saturated, a shunt to limit the charging current, or to cut out by voltage division, or to provide first the shunt and then the cut-out by voltage division, thus to complete charging the (dis)chargeable secondary battery.